Thursday, May 31, 2012

The second installment of the University of California production, The Skinny on Obesity, featuring Dr. Robert Lustig and colleagues is entitled Sickeningly Sweet. I've embedded the video at right. I've entitled this installment of my Review & Critique Sickeningly Inaccurate. That is, frankly an understatement about the information presented in this episode. This video epitomizes what's wrong with many of the "anti-establishment" nutritional experts. You do not counter bad science with more bad science. This is what Lustig does here. And it's not controversial -- at least there's some evidence supporting the lipid hypothesis -- but the "science" here is counter to known basic biochemistry and in opposition to the vast majority of the evidence of metabolism such as de novo lipogenesis.

"Sugar because of its unique composition is the only food on the planet that is both fat and carbohydrate at the same time"

"Even fatty fruits, coconut, olive, avocado have no carb. There is no foodstuff on this planet that has both fat and carbohydrate at the same time. It's one or the other, because that's evolution, that's nature, that's what God did."

While it's not a major problem with this presentation, I do think the use of statistics to push an obvious agenda should be called out. Lustig presents 1985 and 2010 caloric intake and diabetes incidence (by %) and then shows that calories only increased by 8% while diabetes rates increased 727%! Yikes, surely calories can't explain it, right? I don't know, I haven't seen the data. But I'm a bit mistrusting of Lustig setting this up and then stating that the increase in sugar consumption does correlate highly with diabetes and that it's 50X more potent in explaining diabetes compared with calories. Now I doubt sugar consumption has increased by even 100% (doubling consumption) from 1985 to 2010. Why no numbers? I also have a hard time guessing at the statistical scenario that makes sugar 50X more potent in explaining diabetes. When a correlation is done, there's a correlation coefficient, r or R, and R^2 is a value used to say X% of the variability in B is explained by its correlation with A. I have a hard time believing that R's for calories and sugar are 0.1 and 0.7 respectively, giving R^2 of 0.01 and 0.49 respectively, approximating the 50 fold difference he reports.

The ABSURD Contention that Sugar is the only Foodstuff that is Fat + Carb together

Let's repeat the direct quotation of what Lustig says in this regard. After a food history lesson where he says we became gourmets when we put fat+carb on one plate, and gourmands when we put fat+carb in one food. A quick Wikipedia search tells me that in 1528 the Spaniards started sweetening chocolate. But then:

"Sugar because of its unique composition is the only food on the planet that is both fat and carbohydrate at the same time. Even fatty fruits, coconut, olive, avocado have no carb. There is no foodstuff on this planet that has both fat and carbohydrate at the same time. It's one or the other, because that's evolution, that's nature, that's what God did."

It's true that few whole foods found in nature are high in both carbs and fats. I don't think the human metabolism evolved or adapted to eating large quantities of both at the same time because of this fact. But the oily fruits he describes do contain some carb, and we can add nuts and select legumes that also contain both. Milk would be the only food I can think of is relatively high in both. But Lustig is claiming that, say, a high sugar melon like a cantaloupe is a high fat + carb food? Or frankly any fruit. Bananas are high fat + carb? He's using the fact that some fructose is converted to fatty acids through DNL after the food has been absorbed and metabolized to make a definitive claim -- biochemically inaccurate on its face -- that sucrose is both a carbohydrate and a fat at the same time. NOT TRUE.

Fructose Metabolism again - de novo lipogenesis is not what it's cracked up to be in humans

Lustig has been at this gig long enough to have investigated this further. Several critics have pointed out factual errors enough times that he should have fixed this by now. It's a "mistake" he may have made early on. Now it's not a "mistake", it's a misleading lie told to convince you that sugar is inherently toxic by virtue of what it does to your mitochondria. I imagine this is the sort of "white lie" that is tolerated by members working for some "good cause". Please tell me how replacing the demonization of saturated fats and cholesterol with bastardized science to demonize sugar is productive.

Fructose & Fatty Liver & Insulin Resistance

I'll give Gary Taubes this, he is usually pretty careful to add words like "probably", "could be", "might be" in with his theories. Lustig does no such thing. He speaks from a position of authority as if this is all settled science. No doubt this is why his YouTube video went viral, and it sounds convincing until you take a closer look. To me the whole sucrose = carb + fat claim is enough to just shut this guy off. He's either not smart enough to understand basic biochemistry or he's being intellectually dishonest to hype fear. I know where I'm leaning on that. However even if we presume he's correct, that the majority of fructose going to the liver is turned to fat and causing fatty liver, the link between fructose per se (e.g. without caloric excess) and NAFLD is far from clear, and the link between NAFLD and insulin resistance is as well. I haven't seen any evidence that DNL "constipates" your mitochondria, that's for sure!

SUMMARY: Excessive deposition of fat in the liver (hepatic steatosis) is frequently accompanied by hepatic insulin resistance. Whether this correlation is due to a causal relationship between the conditions has been the subject of considerable debate, and the literature abounds with conflicting data and theories. ...

CONCLUSIONS: To date, no specific lipid has been shown to be both necessary and sufficient to cause hepatic IR. The available data indicate that the accumulation of neutral TGs is not causative. It also seems clear that, at the whole tissue level, excessive bioactive lipids, such as DAGs or ceramides, do not fulfill a strict causative relationship, as they are not always sufficient. Whether specific species of such bioactive lipids within specific compartments of hepatocytes can cause hepatic IR remains an active area of investigation.

Another possibility is that different routes lead to hepatic IR, and excess bioactive lipids act as contributing factors. Other processes, such as ER stress or inflammation, also may be sufficient as contributors in some circumstances. In this manner, the accumulation of different lipids, such as DAGs or ceramides, may act as contributing factors, which when combined with other contributing factors, result in a cellular state that is sufficient, but not required, to cause hepatic IR. ...

Fructose is only safe if you're starving or just ran a marathon:

What was I saying about exaggeration recently? This is needless exaggeration. First, there's a lot of evidence that regular moderate alcohol consumption can even be beneficial. What's to say the same isn't true for fructose? Not saying it is, but what's to say it's not? But this is building on the only athletes can eat carbs meme I'm seeing bantied around these days. As if you have to be training several hours a day to be "allowed" to oxidize glucose. Nonsense. We were more active in the 60's, but the percentage of athletes in the population wasn't higher yet we ate carbs and sugar. This stuff is unnecessary hyperbole and it ultimately undermines Lustig's agenda.

Fructose is just like Alcohol:

I'm tired of this one. First, because it's not true. Fructose is metabolized into molecules that are considered benign by Lustig in the diet: glucose and saturated fat. Further it is metabolized to synthesize glycogen. Alcohol .... not so much! So this graphic he uses rises to the level of deliberate deception at this point.

I'm not sure what I'll do with the rest of this series. Perhaps do a highlights but I had a hard time slogging through it the first time. This episode is enough to discredit this man and question the veracity of everything he puts forth on this topic.

10 comments:

6:08 - "If you're starving or glycogen depleted because you just ran a marathon then fructose and *alcohol* can be used to rebuild your energy stores..."

I thought alcohol was always burned and never stored. How can it be used to rebuild energy stores??

In general I found this series hard to watch, and not just because of the bad science. Lustig seems to talk very slowly and deliberately, and he occasionally looks like he's talking to the wall. He reminds me a bit of William Shatner. And what's with the dramatic music and slo-mo shots of fat people. Does anyone really find this sort of thing engaging?

I have some pure dextrose (purchased at a wine making shop; grocery chains don't carry it any more) and some pure fructose (a local grocer carries it)

I can't tell the sweetness difference between taking a spoon of the two powders straight. They are different - the fructose feels warmer[0] the glucose "attack" or "onset of sweet taste" seems quicker (and leaves quicker). But for straight sweetness I aint sensing no diff.

[0] I earlier guessed exothermic heat of dissolution, but maybe fructose twiddles a tiny bit with the same sensors/receptors that capsaicin does

I'm not one to talk, but he actually looks slimmer (in the face) here than in other videos/pics. So either he's a junk food junkie or he's practicing what he's preaching and not faring much better than those he maligns. Eh? SIGH!

it's unbelievable the way that whole crowd of chubby-to-fat LC'ers & the Sugar-is-the-Devil posse both love to ridicule people like Jillian Michaels, when to me she looks amazing & the fact she got there with hard physical work and discipline with her eating makes all the more inspiring to me. In fact, I just got sent the 4-DVD set "28 Day Transformation" by NYC-based trainer Robert Brace & it's very much in the Jillian vein of things - eat properly + do a combo of weights & high-intensity interval-cardio = real results. Which I'd prefer rather than boo-hoo'ing over my "damaged", coconut-oil slathered metabolism or butter-drenched "mysteriously" misbehaving mitochondria.

I wonder if Merry Lustig been accepted as role model by parents of the children who frequent his clinic?He has placed himself in an intellectual cleft stick re CHOs, as he is a lo-fatter in accordance with AHA recommendations.

Consequently, the ONLY mono-saccharide he can condemn is FRUCTOSE.

I smile with private satirical amusement when Eenfeldt uses selective Lustig interviews as support for his own views.

This is just so much "white lie" presentation a la Hahn.

To quote Jimmy the Snake(Oil)Handler: Hay-Soos swept (the temple out of Pharisees.)

Where I think Lustig is on the money is in linking Fox01 overstimulation by fructose to DM2. But this is so technical it's probably not in the presentation. It is in the written thesis of Lustig et al. that I've seen. Push up Fox01 in the nucleus of a hepatocyte (HCV does this) and you get lipogenesis and gluconeogenesis at the same time, the hallmark of DM2.Inhibit Fox01 and you get increased insulin output in beta cells and even insulin being produced by intestinal neuroendocrine cells (now that's interesting).

What's missing is the Zone diet, where equal fat and carb rations still give OK results; what all these healthy fad diets that more-or-less work (Atkins, Ornish, Mediterranean, Zone) have in common is - no sugar!I can't believe Lustig missed that.